The physical and other properties of composites made from organic resin(s) plus inorganic substance(s) can be modified and/or improved by silane compounds which contain both silicon-bonded hydrocarbonoxy and organofunctionalized (methacryloxy, glycidoxy, amino, etc.) alkylene or alkyleneoxyalkylene. This occurs because these silane compounds become interposed between the organic resin and inorganic substance due to the different properties of the organofunctional group and the silicon-bonded hydrocarbonoxy. These types of silane compounds are widely employed as silane coupling agents, and examples here are silane compounds with the following chemical formulas. ##STR1##
However, organopentasiloxane carrying organofunctionalized alkylene or alkyleneoxyalkylene at one molecular chain terminal and silicon-bonded hydrocarbonoxy at the other molecular chain terminal has been heretofore unknown.